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revision 491 by ph10, Mon Mar 1 17:45:08 2010 UTC revision 584 by ph10, Wed Jan 12 11:41:55 2011 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.02 01-Mar-2010  Version 8.12 12-Jan-2011
5    ------------------------
6    
7    1.  Fixed some typos in the markup of the man pages, and wrote a script that
8        checks for such things as part of the documentation building process.
9    
10    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
11        --match-limit and --recursion-limit options (added for 8.11). In
12        particular, this made one of the standard tests crash. (The integer value
13        went into the wrong half of a long int.)
14    
15    
16    Version 8.11 10-Dec-2010
17    ------------------------
18    
19    1.  (*THEN) was not working properly if there were untried alternatives prior
20        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
21        backtracked to try for "b" instead of moving to the next alternative branch
22        at the same level (in this case, to look for "c"). The Perl documentation
23        is clear that when (*THEN) is backtracked onto, it goes to the "next
24        alternative in the innermost enclosing group".
25    
26    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
27        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
28        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
29        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
30        (*THEN).
31    
32    3.  If \s appeared in a character class, it removed the VT character from
33        the class, even if it had been included by some previous item, for example
34        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
35        of \s, but is part of the POSIX "space" class.)
36    
37    4.  A partial match never returns an empty string (because you can always
38        match an empty string at the end of the subject); however the checking for
39        an empty string was starting at the "start of match" point. This has been
40        changed to the "earliest inspected character" point, because the returned
41        data for a partial match starts at this character. This means that, for
42        example, /(?<=abc)def/ gives a partial match for the subject "abc"
43        (previously it gave "no match").
44    
45    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
46        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
47        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
48        has an implication that the given string is incomplete (because a partial
49        match is preferred over a full match). For this reason, these items now
50        give a partial match in this situation. [Aside: previously, the one case
51        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
52        match rather than a full match, which was wrong by the old rules, but is
53        now correct.]
54    
55    6.  There was a bug in the handling of #-introduced comments, recognized when
56        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
57        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
58        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
59        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
60        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
61        places in pcre_compile().
62    
63    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
64        comments when looking ahead for named forward references to subpatterns,
65        the only newline sequence it recognized was NL. It now handles newlines
66        according to the set newline convention.
67    
68    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
69        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
70        cater for a lack of strerror(). These oversights have been fixed.
71    
72    9.  Added --match-limit and --recursion-limit to pcregrep.
73    
74    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
75    
76    11. When the -o option was used, pcregrep was setting a return code of 1, even
77        when matches were found, and --line-buffered was not being honoured.
78    
79    12. Added an optional parentheses number to the -o and --only-matching options
80        of pcregrep.
81    
82    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
83        can match an empty string. The code to do it in pcretest and pcredemo
84        needed fixing:
85    
86        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
87            only one byte after an empty string match just before CRLF (this case
88            just got forgotten; "any" and "anycrlf" were OK).
89    
90        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
91            mode when an empty string match preceded an ASCII character followed by
92            a non-ASCII character. (The code for advancing by one character rather
93            than one byte was nonsense.)
94    
95        (c) The pcredemo.c sample program did not have any code at all to handle
96            the cases when CRLF is a valid newline sequence.
97    
98    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
99        as a starting offset was within the subject string. There is now a new
100        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
101        negative or greater than the length of the string. In order to test this,
102        pcretest is extended to allow the setting of negative starting offsets.
103    
104    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
105        starting offset points to the beginning of a UTF-8 character was
106        unnecessarily clumsy. I tidied it up.
107    
108    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
109        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
110    
111    17. Nobody had reported that the --include_dir option, which was added in
112        release 7.7 should have been called --include-dir (hyphen, not underscore)
113        for compatibility with GNU grep. I have changed it to --include-dir, but
114        left --include_dir as an undocumented synonym, and the same for
115        --exclude-dir, though that is not available in GNU grep, at least as of
116        release 2.5.4.
117    
118    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
119        characters from a string of bytes) have been redefined so as not to use
120        loops, in order to improve performance in some environments. At the same
121        time, I abstracted some of the common code into auxiliary macros to save
122        repetition (this should not affect the compiled code).
123    
124    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
125        compile-time error is now given if \c is not followed by an ASCII
126        character, that is, a byte less than 128. (In EBCDIC mode, the code is
127        different, and any byte value is allowed.)
128    
129    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
130        START_OPTIMIZE option, which is now allowed at compile time - but just
131        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
132        to pcregrep and other applications that have no direct access to PCRE
133        options. The new /Y option in pcretest sets this option when calling
134        pcre_compile().
135    
136    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
137        back references. Groups containing recursive back references were forced to
138        be atomic by that change, but in the case of named groups, the amount of
139        memory required was incorrectly computed, leading to "Failed: internal
140        error: code overflow". This has been fixed.
141    
142    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
143        pcretest.c, to avoid build problems in some Borland environments.
144    
145    
146    Version 8.10 25-Jun-2010
147    ------------------------
148    
149    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
150        THEN.
151    
152    2.  (*ACCEPT) was not working when inside an atomic group.
153    
154    3.  Inside a character class, \B is treated as a literal by default, but
155        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
156        causes the error). The code is unchanged, but I tidied the documentation.
157    
158    4.  Inside a character class, PCRE always treated \R and \X as literals,
159        whereas Perl faults them if its -w option is set. I have changed PCRE so
160        that it faults them when PCRE_EXTRA is set.
161    
162    5.  Added support for \N, which always matches any character other than
163        newline. (It is the same as "." when PCRE_DOTALL is not set.)
164    
165    6.  When compiling pcregrep with newer versions of gcc which may have
166        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
167        declared with attribute warn_unused_result" were given. Just casting the
168        result to (void) does not stop the warnings; a more elaborate fudge is
169        needed. I've used a macro to implement this.
170    
171    7.  Minor change to pcretest.c to avoid a compiler warning.
172    
173    8.  Added four artifical Unicode properties to help with an option to make
174        \s etc use properties (see next item). The new properties are: Xan
175        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
176    
177    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
178        use Unicode properties. (*UCP) at the start of a pattern can be used to set
179        this option. Modified pcretest to add /W to test this facility. Added
180        REG_UCP to make it available via the POSIX interface.
181    
182    10. Added --line-buffered to pcregrep.
183    
184    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
185        studied, and the match started with a letter with a code point greater than
186        127 whose first byte was different to the first byte of the other case of
187        the letter, the other case of this starting letter was not recognized
188        (#976).
189    
190    12. If a pattern that was studied started with a repeated Unicode property
191        test, for example, \p{Nd}+, there was the theoretical possibility of
192        setting up an incorrect bitmap of starting bytes, but fortunately it could
193        not have actually happened in practice until change 8 above was made (it
194        added property types that matched character-matching opcodes).
195    
196    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
197        possible starting bytes for non-anchored patterns.
198    
199    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
200        \R, and also a number of cases that involve Unicode properties, both
201        explicit and implicit when PCRE_UCP is set.
202    
203    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
204        input, it could crash or give wrong results if characters with values
205        greater than 0xc0 were present in the subject string. (Detail: it assumed
206        UTF-8 input when processing these items.)
207    
208    16. Added a lot of (int) casts to avoid compiler warnings in systems where
209        size_t is 64-bit (#991).
210    
211    17. Added a check for running out of memory when PCRE is compiled with
212        --disable-stack-for-recursion (#990).
213    
214    18. If the last data line in a file for pcretest does not have a newline on
215        the end, a newline was missing in the output.
216    
217    19. The default pcre_chartables.c file recognizes only ASCII characters (values
218        less than 128) in its various bitmaps. However, there is a facility for
219        generating tables according to the current locale when PCRE is compiled. It
220        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
221        characters, are recognized by isspace() and therefore were getting set in
222        these tables, and indeed these tables seem to approximate to ISO 8859. This
223        caused a problem in UTF-8 mode when pcre_study() was used to create a list
224        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
225        which of course cannot start UTF-8 characters. I have changed the code so
226        that only real ASCII characters (less than 128) and the correct starting
227        bytes for UTF-8 encodings are set for characters greater than 127 when in
228        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
229        altogether.)
230    
231    20. Added the /T option to pcretest so as to be able to run tests with non-
232        standard character tables, thus making it possible to include the tests
233        used for 19 above in the standard set of tests.
234    
235    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
236        reference to a subpattern the other side of a comment that contains an
237        opening parenthesis caused either an internal compiling error, or a
238        reference to the wrong subpattern.
239    
240    
241    Version 8.02 19-Mar-2010
242  ------------------------  ------------------------
243    
244  1.  The Unicode data tables have been updated to Unicode 5.2.0.  1.  The Unicode data tables have been updated to Unicode 5.2.0.
245    
246    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
247        configured.
248    
249    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
250        original author of that file, following a query about its status.
251    
252    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
253        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
254    
255    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
256        quantifier applied to a forward-referencing subroutine call, could compile
257        incorrect code or give the error "internal error: previously-checked
258        referenced subpattern not found".
259    
260    6.  Both MS Visual Studio and Symbian OS have problems with initializing
261        variables to point to external functions. For these systems, therefore,
262        pcre_malloc etc. are now initialized to local functions that call the
263        relevant global functions.
264    
265    7.  There were two entries missing in the vectors called coptable and poptable
266        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
267        I've fixed the data, and added a kludgy way of testing at compile time that
268        the lengths are correct (equal to the number of opcodes).
269    
270    8.  Following on from 7, I added a similar kludge to check the length of the
271        eint vector in pcreposix.c.
272    
273    9.  Error texts for pcre_compile() are held as one long string to avoid too
274        much relocation at load time. To find a text, the string is searched,
275        counting zeros. There was no check for running off the end of the string,
276        which could happen if a new error number was added without updating the
277        string.
278    
279    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
280    
281    11. \K was not working if it appeared in an atomic group or in a group that
282        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
283        \K is "not well defined" if used in an assertion. PCRE now accepts it if
284        the assertion is positive, but not if it is negative.
285    
286    12. Change 11 fortuitously reduced the size of the stack frame used in the
287        "match()" function of pcre_exec.c by one pointer. Forthcoming
288        implementation of support for (*MARK) will need an extra pointer on the
289        stack; I have reserved it now, so that the stack frame size does not
290        decrease.
291    
292    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
293        item in branch that calls a recursion is a subroutine call - as in the
294        second branch in the above example - was incorrectly given the compile-
295        time error "recursive call could loop indefinitely" because pcre_compile()
296        was not correctly checking the subroutine for matching a non-empty string.
297    
298    14. The checks for overrunning compiling workspace could trigger after an
299        overrun had occurred. This is a "should never occur" error, but it can be
300        triggered by pathological patterns such as hundreds of nested parentheses.
301        The checks now trigger 100 bytes before the end of the workspace.
302    
303    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
304    
305    
306  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010
307  ------------------------  ------------------------

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